RFID‐Enabled Visibility and Retail Inventory Record Inaccuracy: Experiments in the Field

Accurate inventory records are key to effective store execution, affecting forecasting, ordering, and replenishment. Prior empirical research, however, shows that retailer inventory records are inherently inaccurate. Radio Frequency Identification (RFID) enables visibility into the movement of inventories in the supply chain. Using two different field experiments, the current research investigates the effectiveness of this visibility in reducing retail store inventory record inaccuracy (IRI). Study 1 used an interrupted time‐series design and involved daily physical counts of all products in one category in 13 stores (8 treatments and 5 controls) of a major global retailer over 23 weeks. Results indicate a significant decrease in IRI of approximately 26% due to RFID‐enabled visibility. Using an untreated control group design with pre‐test and post‐test, Study 2 expands the number of categories to five and the number of stores to 62 (31 treatment and 31 control stores). Results show that the effectiveness of RFID in reducing IRI varies by category (ranging from no statistically significant improvement to 81%). Results also suggest that RFID ameliorates the effects of known determinants of IRI and provide the key insight that the technology is most effective for product categories characterized by these determinants.     

Misplaced Inventory and Radio‐Frequency Identification (RFID) Technology: Information and Coordination

Misplaced inventory is a major operational problem in many supply chains. Radio‐frequency identification (RFID) technology has been publicized as a promising solution for the misplaced inventory. Adoption of this technology has a fixed cost and variable cost of implementation, which can cause incentive issues in the supply chain. In this paper, we consider a supply chain under misplacement of inventory subject to uncertain demand. We study both centralized and decentralized cases and identify the conditions to coordinate the supply chain under implementation of RFID. We show that the incentives of the parties for investing in the technology are not perfectly aligned in the existence of the fixed cost of investment. Based on the relative payments of the parties for the fixed cost of investment, the incentives to adopt RFID can be characterized into regions, where we observe only one party or two parties benefiting from the technology when the tag price falls in a region specified in the paper. We further establish the effects of changes in mean and variance of a uniform demand on the incentives for investing in RFID and find that the incentives of the firms may indeed decrease as demand becomes more variable.     

基于RFID技术的供应链投资决策及协调策略研究

本文以单制造商和单零售商组成的两级供应链为研究对象,基于链上成员是否投资RFID技术,考虑四种情景:供应链成员均不投资RFID,仅零售商投资RFID,仅生产商投资RFID及供应链成员共同投资RFID。采用Newsvendor模型建立四种情景时链上成员的收益模型,得出Stackelberg均衡解和供应链成员的最优期望收益,探讨了RFID技术投资对各情景时链上成员收益的影响,得到了供应链成员共同投资RFID时的协调策略。研究表明:当RFID标签成本和零售商库存不准确率在相应的阈值内,零售商或制造商单独投资RFID技术均能提升自身收益,同时对链上其他成员的收益存在"正外部性";此外,收益共享契约能够有效地协调链上成员共同投资RFID技术后的供应链,并且该协调思想丰富并拓展了供应链投资RFID技术的协调研究。     

基于RFID技术的双供应链投资决策研究

本文考虑零售商主导的分别由一个供应商和一个零售商组成的两条竞争型供应链中,当两个供应商都未投资RFID技术、只有一个供应商投资RFID技术以及两个供应商同时投资RFID技术时,考虑供应商成本结构的差异,对比分析供应链的投资决策。由于模型解析解过于复杂,本文通过算例分析,着重考虑产品的替代率、RFID标签价格以及库存可获得率三个因素对供应链成员利润的影响。结果表明两条供应链对RFID技术的投资决策会因成本结构和产品替代率的不同而发生变化,其中在两个供应商生产成本差异较大且产品竞争强度较低时,生产成本较高的供应商更愿意投资RFID技术,而生产成本较低的供应商不愿意投资RFID技术,两个零售商则希望使用RFID技术,所以此时仅会有一条供应链上的成员达成一致,决定投资使用RFID技术。     

供应链企业投资RFID技术的博弈均衡研究

本文以两条竞争供应链（每条供应链均包含一个制造商和一个零售商）为研究对象,基于其是否投资无线射频识别（Radio Frequency Identification,RFID）技术,分别构建了两条供应链均不投资RFID（N情景）、供应链1投资RFID（S1情景）,供应链2投资RFID（S2情景）,及两条供应链均投资RFID（T情景）的收益模型,求解出相应的最优解并探讨供应链投资RFID的均衡策略。研究发现：相较于N情景,单条供应链投资RFID技术对其竞争供应链成员收益产生"负外部性"。当RFID成本较低时,供应链的均衡策略为T情景;当RFID成本较高时,错放率较低的供应链不采用RFID技术,其竞争供应链将采用RFID技术以提高自身的竞争力。     

Information‐Sensitive Replenishment when Inventory Records Are Inaccurate

Inspired by recent empirical work on inventory record inaccuracy, we consider a periodic review inventory system with imperfect inventory records and unobserved lost sales. Record inaccuracies are assumed to arrive via an error process that perturbs physical inventory but is unobserved by the inventory manager. The inventory manager maintains a probability distribution around the physical inventory level that he updates based on sales observations using Bayes Theorem. The focus of this study is on understanding, approximating, and evaluating optimal forward‐looking replenishment in this environment. By analyzing one‐ and two‐period versions of the problem, we demonstrate several mechanisms by which the error process and associated record inaccuracy can impact optimal replenishment. Record inaccuracy generally brings an incentive for a myopic manager to increase stock to buffer the added uncertainty. On the other hand, a forward‐looking manager will stock less than a myopic manager, in part to improve information content for future decisions. Using an approximate partially observed dynamic programming policy and associated bound, we numerically corroborate our analytical findings and measure the effectiveness of an intelligent myopic heuristic. We find that the myopic heuristic is likely sufficiently good in practical settings targeting high service levels.     

库存成本变化的VMI供应链协调

提出了库存成本变化的经济订货批量(EOQ)模型,基于该模型研究了库存成本变化时供应商管理库存(VMI)系统的最优协议问题。在该系统中,订货商和供应商达成缺货成本共担协议：当缺货发生时,供应商需要向订货商支付缺货补偿。订货商和供应商分散决策,订货商通过设计协议来减少其成本,而供应商通过制定补货决策来缩小自身成本。通过与传统系统和整合系统的比较,得出了库存成本变化时VMI系统的最优补货决策和缺货成本共担协议。采用数值算例验证了分析结果。结果表明,当且仅当供应商预期成本等于整合系统的最小总成本与固定缺货罚金之和时,VMI系统与整合系统具有相同的补货决策和系统绩效,即能够实现供应链协调。     

制造商RFID策略与零售商窜货策略的动态博弈分析

考虑由单一制造商、单一零售商及两个独立市场(高端市场和低端市场)组成的供应链系统,针对零售商可能窜货的问题,建立了制造商RFID采纳和零售商窜货的动态博弈模型,分析了零售商窜货策略和制造商RFID采纳策略,研究了RFID双重效应(成本效应和惩罚效应)对灰色市场、企业收益及社会福利的影响。研究表明：1)RFID可以有效抑制零售商的窜货行为。当不存在RFID时,若市场差异较大,零售商窜货,若市场差异较小,零售商不窜货。而当存在RFID时,即使市场差异足够大,若RFID惩罚效应较强,零售商不窜货;2)RFID可能使得零售商窜货反而会增加制造商的收益。当不存在RFID时,零售商窜货总是降低制造商的收益。而当存在RFID时,若市场差异较小且RFID成本效应较强,零售商窜货增加了制造商的收益;3)制造商并非总是采纳RFID,其策略取决于市场差异的大小和RFID双重效应的强弱。     

Heuristic Coordination of Decentralized Inventory Systems Using Induced Backorder Costs

In this paper, we investigate a one‐warehouse multiple‐retailer system, where the inventory control decisions are coordinated using a near optimal induced backorder cost, β*. All installations use continuous review installation‐stock (R, Q) policies. The analysis builds on an approximation model where the stochastic warehouse delays are replaced by their correct averages. The contributions include insights as to how β* is influenced by system parameters, and the determination of simple closed form β* estimates. The latter offering a practical means to achieve coordinated control of large size systems.     

碳税政策下随机双渠道库存与协调研究

构建碳税政策下由单个制造商和单个零售商组成的双渠道供应链模型,在考虑渠道之间缺货转换的基础上,研究批发价格合约和双向收入共享契约下渠道间双渠道库存竞争问题,并设计了由双向收入共享合约和转移支付机制组成的组合合约机制使制造商和零售商实现共赢,以此保证合约的有效执行。研究表明：批发价合约和双向收入共享合约下,制造商分别通过调控批发价格和收入分享比例来调控双渠道的库存水平,其中网络渠道最优库存水平随着零售渠道单位碳排放量增加而增加,零售商的库存水平随着其单位碳排放量增加而减少。进一步分析了渠道间单位产品碳排放差异对批发价格,以及传统零售渠道和网络渠道库存水平的影响如何受到缺货转换率和碳税税率的调节。     

供应链库存协调策略研究

研究和分析了直运型供应链通过共同补给期协调库存的策略问题。在该供应链中,单一供应商提供单一产品给面临随机需求的单一零售商。在所提出的库存协调策略条件下,供应商指定共同补给期,当零售商按供应商指定的共同补给期作为其订货周期时,供应商提供零售商一定的价格折扣。这种协调策略可以视为Stackelberg博弈。在阐述了解决该博弈问题的方法后,进行了数值实验,分析了采用这种协调策略的利益。     

供应链库存合约研究

研究了制造商与其供应商的供应链最优库存策略和在非合作情况下的库存策略,比较分析了两种情况下的库存策略,并设计了库存合约;分析表明,制造商通过设计有效的转移支付合约,可以实现供应链库存的最优化。     

基于整数乘子的多阶段多顾客供应链库存协调模型的改进研究

首先研究了Khouja(2003)[1]提出的三种多阶段多顾客供应链库存协调机制及其模型。在分析其第三种模型(厂商2的整数次幂)的解的遗漏性与实际应用的苛刻条件基础上,提出了基于整数乘子的多阶段多顾客供应链库存改进模型,经过数值实证了改进模型能得到更优结果。研究提出的改进模型更具有普适性,适应供应链精细化运营与管理的要求。     

Coordination in a Single‐Supplier,Multi‐Retailer Distribution System: Supplier‐Facilitated Transshipments

We consider supplier‐facilitated transshipments for achieving supply chain coordination in a single supplier, multi‐retailer distribution system with non‐cooperative retailers. The previous transshipment literature has focused on coordination through retailer‐negotiated transshipments and thus does not consider the supplier's decision‐making. In contrast, in this study, we assume the supplier is an active participant in the system and we seek to understand how the supplier can facilitate the implementation of coordinating transshipments. We study a two‐period model with wholesale orders at the start of the first period and preventive transshipments performed at the start of the second period. Inspired by a supplier‐facilitated transshipment scheme observed in practice, we assume the supplier implements transshipments through a bi‐directional adjustment contract. Under this contract, each retailer can either buy additional inventory from, or sell back excess inventory to, the supplier. We show that coordination can be achieved through carefully designed contracts with state‐dependent adjustment prices and a wholesale price menu. We demonstrate that the supplier's role in facilitating coordinating transshipments is critical. In addition, we use our understanding of the coordinating contract form to derive some simpler and easier‐to‐implement heuristic contracts. We use a numerical study to demonstrate the value, to the supplier, of using the coordinating adjustment and wholesale prices, and to evaluate the heuristics’ performance.     

考虑供应链信用水平的存货质押率研究

供应链融资可以提高中小企业的信用水平和贷款能力。考虑单一核心企业和单一零售商构成的二级供应链,产品市场需求为典型的报童模型,给出了供应链信用和信用乘数的概念,建立了考虑供应链信用水平的银行质押率决策模型,得到供应链存货质押融资情况下银行的最优质的押率,研究了信用乘数、存货质押量、回购价、回购率、银行的损失规避程度等诸多要素对银行质押率的影响。研究表明:供应链融资情况下的最优质押率高于零售商单独融资情况下的最优质押率;一定条件下,银行质押率与核心企业信用乘数、回购参数正相关;质押率和存货质押量、银行风险厌恶程度负相关;举例并进行了灵敏度分析。     

有限耐烦期随机库存系统的最优控制

对供应链内部库存系统进行优化控制是提高供应链协调性的一种重要手段。本文针对实际库存活动中普遍存在的有限耐烦期这种现象,综合考虑顾客退货、库存损失等随机因素对最优库存策略的影响,构造出一种更加贴近实际的随机库存系统最优控制模型,并借助于动态规划原理给出了最优控制律的表达式,然后给出了算例及说明。其结果可为随机库存系统的管理决策提供了理论依据,也可为进一步提高供应链的协调性提供了借鉴。     

Quantity Discount‐Based Inventory Coordination: Effectiveness and Critical Environmental Factors

It is understood that quantity discounts provide a practical foundation for coordinating inventory decisions in supply chains. The primary objective of this research is to test, under a variety of environmental conditions, the effectiveness of quantity discounts as an inventory coordination mechanism between a buyer and a supplier. A comprehensive simulation experiment with anova has been designed to investigate the impacts of (1) choice of quantity discount‐based inventory coordination policies, (2) magnitude of demand variation, (3) buyer's and supplier's relative inventory cost structure, and (4) buyer's economic time‐between‐orders on the effectiveness of supply chain inventory coordination. The analytical results confirm that the quantity discount policies have managerial properties as a mediator for inventory coordination. The results also show that the performance of quantity discount‐based inventory coordination policies is influenced significantly by environmental factors, such as the magnitude of demand variation, the buyer's and the supplier's inventory cost structure, and the buyer's economic time‐between‐orders.     

Durability,Transit Lags,and Optimality of Inventory Management Decisions

Two laboratory experiments on a single‐echelon inventory task show that inventory durability interacts with transit lags to create order volatility that exceeds demand volatility. Thus, inventory durability and transit lags cause managers to deviate from inventory decision optimality. Durability creates a large increase in order volatility because players adjust orders insufficiently to reflect current inventory and backlogs, much as they adjust orders insufficiently to reflect holding and backlog costs in newsvendor studies (e.g., Schweitzer and Cachon 2000). Transit lags exacerbate non‐optimal ordering by interfering with players' ability to correct prior errors. Our results suggest that non‐optimal inventory decisions can be driven by inventory and supply chain characteristics, even in the absence of the coordination and information sharing problems studied by Croson et al. (2005) and Sterman (1989a,b). We also examine the influence of features related to personality. We find little evidence that the interactive effects of durability and transit lags are altered by need for cognition, impulsiveness, or locus of control, suggesting that these features make supply chain management extremely difficult. These results imply that retailers and their upstream partners must consider the characteristics of their product and supply chains when interpreting demand signals received from downstream partners.     

基于系统动力学的库存管理研究

在讨论系统动力学相关理论及其应用现状的基础上,研究了供应商代管库存模式(VenderManagedInventory,VMI)的管理思想,并借助建模平台STELLAithink,建立了供应链环境下库存管理的系统动力学仿真模型,并对模型的运行和模拟结果进行了分析。     

供应链提前期供需联合优化库存模型研究

本文研究由生产商和客户组成的二级供应链库存联合优化问题, 假设提前期服从均匀分布, 提前期订货受生产商的生产行为和客户的订货行为的制约, 建立了以库存成本为目标函数的供应链提前期供需库存模型, 提出了联合优化解决方案, 证明了目标函数在最优订货量和最优订货次数处存在最小目标值。在此基础上, 分析了提前期对供应链库存联合优化决策的影响。数据分析表明, 联合优化决策方法的库存成本曲线始终在分散决策优化方法的成本曲线的下方, 因此联合决策方法是非常有效的。